Chapter 1
Introduction
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J. Fahey* and L. Maelia Division of Natural Science, Mount Saint Mary College, Newburgh, New York 12550, United States *E-mail:
[email protected] This chapter outlines the development of green chemistry as an alternative way of considering chemical processes. It describes the principles that define green chemistry and explains how the following chapters utilize green chemistry concepts in the teaching laboratory.
Since the 1960s when it became evident that our environment could not sustain the insults of human activity, chemists have considered ways to mitigate their impact on the planet. Initially, concern was almost exclusively about removing toxic chemicals in the environment. Today, chemists’ concern for the environment is much more multidimensional, ranging from designing processes that use fewer and less toxic chemicals, to designing molecules that are themselves less toxic and that do not remain in the environment after they have outlived their usefulness. Greening a chemical reaction has become more than an afterthought, but is built into the entire process, from choosing the source for the reactants, to the disposition of the products, and along the way considering the quantity and toxicity of byproducts, the chemical and energy efficiency of the reaction, and the safety of the entire process. This change has been gradual, occurring slowly over time. Green chemistry, as we know it today, revolves around a set of twelve principles that were outlined by Anastas and Warner in 1998 (1): 1.
Prevention It is better to prevent waste than to treat or clean up waste after it has been created.
© 2016 American Chemical Society Fahey and Maelia; Green Chemistry Experiments in Undergraduate Laboratories ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
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2.
Atom Economy Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product.
3.
Less Hazardous Chemical Syntheses Wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment.
4.
Designing Safer Chemicals Chemical products should be designed to affect their desired function while minimizing their toxicity.
5.
Safer Solvents and Auxiliaries The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary wherever possible and innocuous when used.
6.
Design for Energy Efficiency Energy requirements of chemical processes should be recognized for their environmental and economic impacts and should be minimized. If possible, synthetic methods should be conducted at ambient temperature and pressure.
7.
Use of Renewable Feedstocks A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable.
8.
Reduce Derivatives Unnecessary derivatization (use of blocking groups, protection/ deprotection, temporary modification of physical/chemical processes) should be minimized or avoided if possible, because such steps require additional reagents and can generate waste.
9.
Catalysis Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.
10. Design for Degradation Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment. 11. Real-Time Analysis for Pollution Prevention Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances. 2 Fahey and Maelia; Green Chemistry Experiments in Undergraduate Laboratories ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
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12. Inherently Safer Chemistry for Accident Prevention Substances and the form of a substance used in a chemical process should be chosen to minimize the potential for chemical accidents, including releases, explosions, and fires. Just over twenty-five years ago, the United States Environmental Protection Agency (EPA) first introduced the term Green Chemistry (2). Since it’s introduction, green chemistry has infiltrated both industry and academia. In the early 90’s a course entitled, Introduction to Green Chemistry, was first taught at Carnegie Mellon University (3). By the late 90’s the University of Massachusetts at Boston established the first doctoral program in Green Chemistry (4). In 1997, the Green Chemistry Institute (GCI) was founded as an independent nonprofit organization to advance green chemistry principles in the scientific community. In 2001, the GCI joined forces with the American Chemical Society (ACS), the largest scientific society in the world, and became the ACS-GCI (5). The ACS-GCI employs a three pronged approach to expanding knowledge about green chemistry: via scientific research, educational outreach, and industry participation (6). 2016 marks the 20th anniversary of the annual Green Chemistry & Engineering Conference first sponsored by GCI. The first conference brought together industry leaders and government in an effort to make industrial processes more environmentally friendly. Subsequent conferences have expanded their reach to include students and green chemistry education. It is one of many national and international conferences with a green chemistry focus (7). While industry has seen the need and benefits of applying principles of environmental concern, green chemistry has more slowly been adopted by the education community. However, we are doing students a disservice if we send them off to industry, government, or graduate school without the knowledge and skills needed to protect the environment. A number of resources are available for instructors to learn about greening their curriculum. The ACS Green Chemistry site provides extensive lists of resources for both students and educators (8), as does the green chemistry site of the US Environmental Protection Agency (EPA) (9). There are a few texts and laboratory manuals devoted to green chemistry (10–15). This book builds on the work that has been done previously, and is a product of a chemical education symposium held at the 2015 Northeast Regional Meeting of the American Chemical Society in Ithaca, NY. In this book, we have compiled a number of ways that green chemistry can be incorporated into the undergraduate teaching laboratory. We begin with an overview of the green chemistry experiments in organic chemistry published since 2012, when Andrew Dicks’ “Green Organic Chemistry in Lecture and Laboratory” was published (10). The twelve green chemistry principles can be seen throughout the experiments described here. A common principle is one that is easily understood as a basic tenet of greening a chemical process: using less hazardous substances in chemical synthesis and using safer solvents for extractions and separations. By using safer starting materials, the experiments of Fahey and Bastin show how Principle 3, Less Hazardous Chemical Syntheses, can be applied. The experiments of Bastin, Manchanayakage, and Wissinger 3 Fahey and Maelia; Green Chemistry Experiments in Undergraduate Laboratories ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
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all use fewer and/or safer solvents (Principle 5). The use of catalysts marks the work of Gross and Fahey (Principle 9), while the efficiency of the synthetic route is a focus of the experiments of Fishback and Manchanayakage (Principle 2). Wissinger’s experiment also uses renewable feedstocks (Principle 7) and designs products for ultimate degradation (Principle 10). Bastin’s chapter explains how students are actively involved in seeking green alternatives for their laboratory experiments. The chapter by Barcena encourages students to consider the toxicity of the chemicals used, even everyday chemicals with which students are familiar. These experiments can be adopted or adapted for use in the undergraduate laboratory, and provide ideas and inspiration for greening your own laboratory experiments.
References 1. 2. 3. 4.
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10. 11. 12. 13.
Anastas, P. T. ; Warner, J. C. Green Chemistry: Theory and Practice; Oxford University Press: New York, 1998. Andraos, J.; Dicks, A. P. Green chemistry teaching in higher education: a review of effective practices. Chem. Educ. Res. Pract. 2012, 13, 69–79. Collins, T. J. Introducing green chemistry in teaching and research. J. Chem. Ed. 1995, 72, 965. American Chemical Society. ACS History of Green Chemistry, June 19, 2016. https://www.acs.org/content/acs/en/greenchemistry/what-is-greenchemistry/history-of-green-chemistry.html (accessed July 6, 2016). American Chemical Society. ACS History of Green Chemistry, June 21, 2016. https://www.acs.org/content/acs/en/greenchemistry/what-is-greenchemistry/history-of-green-chemistry.html (accessed June 26, 2016). American Chemical Society. ACS Green Chemistry Institute, June 24, 2016. https://www.acs.org/content/acs/en/greenchemistry.html (accessed June 26, 2016). American Chemical Society. Green Chemistry Conferences, June 25, 2016. https://www.acs.org/content/acs/en/meetings/ greenchemistryconferences.html (accessed June 26, 2016). American Chemical Society.. Students and Educators, June 21, 2016. https://www.acs.org/content/acs/en/greenchemistry/students-educators.html (accessed June 26, 2016). Environmental Protection Agency. Resources. [Online] April 19, 2016. [Cited: June 26, 2016] https://www.epa.gov/greenchemistry/ resources#education. Dicks, A. P., Ed.; Green Organic Chemistry in Lecture and Laboratory; CRC Press: Boca Raton, FL, 2012. Matlack, A. S.;Dicks, A. P. Problem-Solving Exercises in Green and Sustainable Chemistry; CRC Press: Boca Raton, FL, 2015. Henrie, S. A. Green Chemistry Laboratory Manual for General Chemistry; CRC Press: Boca Raton, FL, 2015. Matlack, A. S. Introduction to Green Chemistry, 2nd ed.; CRC Press: Boca Raton, FL, 2010. 4 Fahey and Maelia; Green Chemistry Experiments in Undergraduate Laboratories ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
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14. Lancaster, M.. Green Chemistry: An Introductory Text, 2nd ed.; Royal Society of Chemistry: London, 2010. 15. Kirchhoff, M., Ryan, M., Eds.; Greener Approaches to Undergraduate Chemistry Experiments; American Chemical Society: Washington, DC, 2002.
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